Pilot-truck.



w. F'. I.I CASEY Il G. cAvIAI.

PILOT TRUCK.

APPLICATION FILED Nov.2 4. IsIs..

Patented July 17, 1917 2'SHEETS-SHEET l.

IIIIAII. wm I/ IIIII I ALIA I.

/MII/e/ww WEL/fa@ (Law/h yW. F. I. CASEY @I G. CAI/IN.

PILOT TRUCK.

' APPLICATION r|LD'Nov.24. 1916.

Patented. July 1 7, 1917.

2 SHEETS-SHEET 2 III y I 3 @7m WILLIAM r. J. CASEY AND eUsTAvE cAvIN, or KINGSTON, ONTARIO, CANADA.

mrow-TRUCK.

Specification of Letters Patent.

Application iiled November 24, 1916. Serial No; 133,227.

To all 'whom t may concern.' Be it known that we, WILLIAM F. J. CASEY and GUs'rAvE CAVIN, both subjects of the King of Great Brit-ain, and residents of the city of Kingston, in the Province of Ontario and Dominion of Canada, have invented` Acertain new and useful Improvements in Pilot-Trucks, of which the following is a full, clear, and exact description.

This invention relates to improvements in pilot trucks for locomotives and the like, and the object of the invention is to provide a pilot truck of lighter weight and smaller size than that ordinarily used.

A further object is to provide a truck in which the resistance to lateral motion may be adjusted so as to remain constant, increasing or decreasing as may be desired.

A still further object is to provide a pilot truck of such structure that the front end of the engine frame may be built lower than is at present the'case, thus permitting the center line of the coupler approximately in the same plane as the center lines of the frame. Y

Various other subsidiary objects will be apparent from the following description.

At the present time, great difficulty is ex perienced in obtaining efficient service from the leading or pilot trucks of locomotives, especially on those locomotives equipped with trucks of the twowheel type. This difficulty is largely due tothe greatly increased size of locomotives in recent years.` The truck most common in use is the swing bolster type. This type of truck has a large number of objectionable features, the chief l of which are its multiplicity of parts, great weight, extreme height, necessitating high front ends to the engine frames to prevent clearance, and its constantly increasing resistance, as it is forced out of center line by flange pressure when the locomotive is taking a curve. j

It has already been proposed to overcome certain of these objections, notably to provide means for maintaining a constant resistance for increasing truck movements. The various changes which have been suggested from time to time do not reduce the number of parts and weight of the truck, nor the height of same. In fact, in some cases, the improvement in one direction is made only at the expense of increased disadvantage in another direction, such as increased weight or multiplicity of parts. Tn practically all trucks, where the aim of thel designer has been to maintain constant resistance tolateral movement, it is essential to have a casting secured between the locomotive frames, technically known as the truck center pin guide, through which the center pin opcrates, and which from the design of the truck must be of very heavy and rigid construction. The application of the weight of the front ,fend of the locomotive to the pilot truck is usually through the medium of a separate equalizing beam.

According to this invention, a mostradical departure from present methods is made in the combination in an integral casting of the radius bar, forwardequalizing beam and truck frame, including the pedestals.v By this design, the usual swing bolster with its links, pins, etc., is entirely eliminated, and the centering and displacement resistance is provided yfor each spring-loaded swinging link moving in a horizontal plane and suitably engaging the locomotive frame. The

.weight of the front end of the locomotive is applied through a spherically curved bearing located under the cylinder casting, which allows for movement of the radius bar and truck.

Inthe drawings which illustrate the invention j Figure 1 is a plan View ofthe truck partly in section on the line 1 1, Fig. 3.

Fig. 2 is a side elevation partly in section on the line 2 2, Fig. 1.

Fig. 3 is a front elevation, partly in section, on the line 3 3, Fig. 1.

Fig. 1 is a rear elevation.

Fig. 5 is an enlarged plan lview* of the centering device.

Fig. 6 is a plan view of a slightly modified form of centering device. 1

Fig. 7 is a fragmentary plan view showing a slightly modified form of the truck, to accommodate elliptic springs instead of the helical springs for which the design of Figs. 1 to 3 is adapted.

Fig. 8 is a planv view illustrating an alternative form of centering device.

Referring more particularly to the drawings, 11 designates a truck casting having integra-l pedestals 12 and an integral radius bar 13. The wearing faces of the pedestals in contact with the journal boxes 14 are protected by renewable plates 15. As will be seen in the drawings, this casting is of hollow or box construction, and therefore Patented July 17, 1917..

very strong. Weight is eliminated where possible without the sacrifice of strength by ope-nings 16 in the walls of the casting. Toward the free end of the radius bar, a bearing 17 is provided for the king pin or center pin 18, ,which is preferably in the form of a heavy cast column depending from the cylinder casting 19 of the locomotive. The bearing 17 is curved in its axial direction, so that the radius bar in addition to having the usual swinging motion around the pin in a horizontal plane, may have a swinging motion in a vertical plane at any angle to the center line of the locomotive, and also may move up or down on the pin. If desired, the lower end of this pin 18 may be steadied by la cross tie extending to the frames. The weight of the locomotive is applied to the truck by means of spherically curved interengaging bearing members 20,

one of which is secured to the cylinder casting and the other of which has sliding movement on the top of the radius bar. The free extremity of the radius bar is connectedby means of a link 21 with the equaliz'ing mechanism of the locomotive, so-that vthe pilot truck at all times takes its predetermined proportion of load. The radius bar also performs the function of a forward equalizing lever.

T he vcentering and resistance device is located substantially within the truck body,

so that it occupies no additional space and enables the locomotive frames to be made much lower than heretofore possible, at the lSame time leaving ample clearance between the frames and truck. The centering device consists essentially of a lever or crank -22 having a pair of supporting pivots 23 at one end thereof spaced equidistantly on opposite sides of the' longitudinal axis.

These pivots are seated in sockets 24 cast A ten-V inor attached to the truck frame. sion link 25' is connected at one of its ends midway between the pivots 23, and at the opposite end carries an adjustably mounted spring cap 26, which is slidably mounted in., guides-27 formed in the truck frame, and

holds` the spring 28 in compression between itself and the spring seat 29 formed integral vwith the truck frame; It will be readily j, understood that as the tension is applied to the centering lever 22 midway between the -two pivots and be held in the position laterally directed force to the free end of the lever causes the same to swing about one of its pivots, lifting the other pivot 4out of its socket, as clearly shown in broken lines, Fig. 5. Such movement advances the point of attachment of thetension link 25, so that the movement is made against the resistance of the spring 28. Itwill be readily understood that as the point of attachment of the tension link, which is the point of application of the spring force, is moving in an arc, the leverage through which the spring force is applied is at its greatest when the centering lever is at rest, and gradually diminishes as the magnitude of movement of the lever from the centering position increases. In this Way the effective resistance of the spring decreases as the lever movement continues. The free end of the centering lever is provided with a slot 30 adapted for the reception of a spherically formed bearing 31, which is slidable in the slot in a 'longitudinal direction and `which has vertically sliding engagement with a pin 32 rigidly mounted between the engine frames. The forward end of the lever is provided with a lug or guide 33 traveling in a slot 34 in the front of the truck frame. The purpose of this lug is merely to support the front end of the lever against movement with the pin 32, when the truck and frame move independently of one another in a vertical direction.

The same result exactly is obtained with the structure shown in Fig. G. In this instance, the centering lever instead of being slotted 4is tapered to a shank 22, whichy slides through a spherically surfaced bearing 31 mounted in vertically disposed guides 30a formed in or attached to the buffer 35. This buffer being rigidly connected with the locomotive frames and virtually forming a part thereof, it may be stated that the bearing is mounted in the frame and the pin on the lever, which is the exact converse of the structure shown in Fig. 5. 1t will be obvious that the centering lever and spring may be mounted on the engine frame and the pin or bearing on the truck, without in any way altering the construction, operation or principle.

In Fig. 7 a slight modification of the truck frame is depicted having an enlarged spring space to permit the use of an elliptic or semielliptic spring over the journal box, instead of the helical springs shown in the preceding figures. As this structure requires a larger and therefore heavier casting and the spring itself is heavier, its use may be considered as limited to the heavier types of locomotives where helical springs are not suitable.

In Fig. 8, an alternative form of centering device is illustrated, in which the conditions prevailing in the foregoing figures are reversed. That is, instead of the centering lever having two vpoints of pivotal support equidistant on opposite sides of the tension link, the lever has only a single point of pivotal support and is provided with links connecting it to the operating spring, said links being secured to the lever equidistantly on opposite sides of its point of support. In this form, the centering lever 22, which may be either of the type shown in this figure or in Fig. 6, is provided with a single centrally disposed pivot 23a bearing in a socket 24a. Tension links 25a are connected to the lever at points equidistant on opposite sides of its pivotal support, and are bent around the remote end of the spring so as to engage a common bearing 26%l on the spring cap 26, arranged substantially in the axis of the spring. These links may be suitably supported in the frame, so that when the lever is inclined, one link draws up the spring and the other recedes out of engagement therewith. In the form shown, the arrangement of pivots is such that the effective resistance of the spring will increase slightlyon the initial movement of the lever, and will then decrease as previously described. It will therefore be understood that by merely shifting the relative positions of the support and link connection to the centering lever, the effective resistance of the spring may be varied as desired. f

The operation of the device is extremely simple. So far as load is concerned, the entire truck casting is a lever pivoted at the bearing 2O and having support at onerend from the wheels and at the opposite end through the evener suspension link 21. The pin 18 takes no load and merely slides through its lbearing 17 as the casting oscillates about the bearing 20. It will thus. be seen that the pin 18 is relieved of substantially all weight load. As the locomotive in advancing strikes a curve, the flange of one or the other of. the truck wheels bears hard against the outside rail, which is at an angle to the direction of travel, so that it forces the wheel in a lateral direction. This force is transmitted through the journal box and truck frame to the centering link 22, one end of which is pivotally supported in the truck frame and the other end of which engages the frame carried pin 32. The entire truck frame moves laterally, pivoting on the pin 18, but as one end of the centeringlever 22 is held by the pin 32,

which has as yet no lateral movement, it is obvious that this lever is tilted, and in tilting compresses the spring 28, as previously described. It is obvious that until the lateral pressure is suflicient to compress the spring 28, there can be no lateral movement of the truck. It will be remembered that the effective resistance of the spring decreases as the inclination of the lever increases. In practice, the result is that once the lateral movement is commenced, less force is required to hold the truck in any position to which it has been moved, and that if the movementI increases, the force required decreases. Therefore, in taking a curve, the lateral thrust of a rail on the wheel flange forces the truck laterally. As advance on the curve continues, the lateral truck movement continues, but as the resistance diminishes, it is obvious that less pressure or lateral thrust on the wheel flanges will be required. It Will thus be seen that with the diminishing resistance, flange pressure diminishes, and therefore the danger of the flange climbing the outside rail diminishes. There is incidentally considerable saving in flange wear. Another important feature is that the decreasing resistance enables the initial resistance of the centering device to be set much higher than is ordinarily possible, so that swaying of the locomotive over the pilot trucky is to a large extent eliminated and such swaying as can not be eliminated is decreased in extent. y

From the foregoing description, it will be seen that in addition to accomplishing decrease of resistance with increase of truck oscillation, the truck itselfis very much more simple in construction than the ordinary trucks. It will also be obvious by comparison of Fig. 2 with a similar View of an ordinary swing bolster pilot truck that the structure has been very greatly lowered, thus permitting lowering of the front ends of the engine frames. Furthermore, additional castings secured between the frames are eliminated, as with this invention it is possible to utilize the existing cylinder or yoke casting. The simplification of structure and the design employed enable a very considerable saving of weight to be effected. In practice, this saving of weight amounts to approximately two t ousand pounds.

I-Iaving thus described our invention, what we claim is 1. In pilot truck construction ofthe inside bearing type, a radius bar, a. pivot supporting said bar for oscillation in a horizontal plane, a further bearing eccentric with respect to said pivot about which the bar oscillates in a vertical plane acting as an equalizing lever, and the suspension link for one end of the truck, said link, pivot and bearing lying in the same vertical plane.

- 2. In pilot truck construction of the inside bearing type, a single member oscillatable in a horizontal plane functioning as a radius bar, andsimultaneously oscillatable in a vertical plane functioning as an equali'zing lever.

3. In pilot truck construction of the inside bearing type, an integral 'Il' .shaped casting comprising truck frame, radius bar and an equalizing beam.

4. In pilot truck construction of the inside bearing type, a. single casting comprising a truck frame, pedestals, radius bar, and an equalizing beam.

5. In pilot truck construction of the 1nside bearing type, a combined radius'bar and y equalizing bea-m, a pin about which said member swings` as a radius bar, and a bearing about which vsaid member swings as an `equalizing beam, said bearingl being slidably mounted with respect tothe member,

said pin and bearing lying in the longitudinal center line of the truck. Y 6. In truck' construction, a single hollow casting comprising atruck frame and a combilled "radius bar and equalizing beam,` a

.truck centering device, and seats in the thickness of said casting for the reception of said centering device.

7. Iny truck construction, a truck frame,

" a centering lever housed in the frame having laterally separate supporting pivots, a tension spring connection between the spring and lever at apoint intermediate the pivots,

and means engaging 'the free end of said lever. y

8. In truck construction, a truck frame, a

centering lever housed therein and movable' bodily with the frame, spring means normally holding said lever in a predetermined position, and means engaging the lever to hold the truck in predetermined position.

9. In pilot truck construction of the inside bearing type, the 'combination with a vehicle frame and a truck frame movable with respect thereto, of a centering device 4 varranged to normally hold said truck frame 11i predetermined relation lto the vehicle frame, including a lever pivotally mounted to va position central with respect to the vehicle framel including a centering lever having spaced pivotal supporting points spaced in the direction of truck frame move# A ment, a centering spring, andconnection between said spring and lever at a point midway between said pivotal supporting points, and a universal joint slidable With respect to said lever, said lever and joint forming a connection between the truck frame and vehicle frame.

l 11. In pilot truck construction of the inside bearing type, the combination with a vehicle frame and a truck frame movable with respect thereto, of-a centering device arranged to constantly urge the truck frame to a position central with respect to the vehicle frame, saidcentering device including a lever mounted in one of the frames and having two points of pivotal support spaced iii the direction of truck frame movement, a centering spring and a connecting link betweensaid spring and the centering lever'attached to the lever intermediate its points of pivotal support and arranged to' exert a gradually decreasing centering effect as the truck frame and centering lever'movement increase, a universal joint connection between said centering lever and the other of said frames, whereby the pull of said spring operates to urge the truck frame to a central position withrespect to the vehicle frame.

. 12.` In truck construction, the combination horizontal "plane and supported against movementl in a vertical plane, vand means f .carried by the other frame having sliding 'engagement with said lever to permit relative vertical movement of the frames without 85 affecting the lever.

l In witness whereof, we have' hereunto set our hands.

WILLIAM F. J. CASEY. leUsTAvE oAviN.

VVitnessesz; A` I B. A. KELLY,

F. HARRIGAN. 

